The present invention relates to a mounting structure including a power supply structure between a power supply and an electronic apparatus such as printed wiring board and a cooling structure to be used for electronic apparatus such as a computer system, and particularly to a power supply structure which is so structured that the power is supplied through a bath plate having a plurality of conductive layers and a mounting structure which is suitable for air cooling by a fan.
An electronic apparatus such as electronic computer system is structured as shown in the side elevation of FIG. 3.
An electronic apparatus 5 is housed in an enclosure 1 which is provided with a door 2 to be opened or closed. Moreover, the housed electronic apparatus 5 is provided with a fan unit 7 and a duct 6 and the electronic apparatus 5 is cooled by air by driving the fan 8.
At the bottom part of enclosure 1, the legs 3 for supporting the enclosure 1 from the floor surface and the casters 4 for transferring the enclosure 1 along the floor surface are further provided.
Such recent electronic apparatus 5 is formed as a semiconductor element such as an LSI which assures high packing density and high speed operations, a one-board substrate on which an electronic circuit is formed by mounting circuit elements on a single multilayered printed wiring board, and a power supply which supplies specified power to said one board substrate.
In the case of such electronic apparatus, the power source supplied to the one board substrate from the power supply has a low drop of voltage through the bus because it is shortened as much as possible and it is also necessary that the cooling efficiency must be high because the one board substrate generates a large amount of heat.
Accordingly, it is generally important for such electronic apparatus that the structure thereof can be formed in compactly without causing any problem in the air cooling system.
The structure of electronic apparatus of prior art has been formed as indicated in the perspective view of FIG. 4.
A unit 10 formed using a one board substrate 19 engaged with the one or both surfaces of a bus plate 13 through the posts 14 and a power supply unit 18 provided with the output terminals 18A, 18B are arranged together. The bus plate 13 is composed of a conductive layer 11, which is provided with mounting holes 11A for mounting on an enclosure frame and is connected to the earth, and conductive layers 12 which are layered on both sides of conductive layer 11 in order to hold it through the insulation materials and are connected to the specified power source voltage.
Moreover, the posts 14 fixed respectively to the conductive layer 11 or conductive layer 12 of bus plate 13 are conductively connected to the predetermined land of the one board substrate 19 with a screw 15 screwed to the threaded hole provided at the end portion of post through the fitting hole of the one board substrate 19.
This post 14 is formed by a flexible conductive material and it should desirably to extensive and compressive. (For details, refer to the Japanese Patent Application No. 59-111280.)
Power supply bars 16, 17 are extended between the bus plate 13 and power supply unit 18, the conductive layer 11 is connected to the power supply bar 16 while the conductive layer 12 is connected to the power supply bar 17 respectively by screwing a bolt 21 to the bus plate 13. Moreover, the power supply bar 16 is connected to the output terminal 18A while the power supply bar 17 to the output terminal 18B respectively by screwing the bolts 20, and the power sources from the output terminals 18A, 18B of power supply unit 18 are supplied to the one board substrate 19 through the bus plate 13 and post 14.
Cooling can be done in such a way that the surface B of one board substrate 19 is cooled by ventilation in the direction of arrow mark D while the space A by ventilation in the direction of arrow mark C.
Such structure however has a problem that the power supply bus is longer and thereby the voltage drops because the power source of power supply unit 18 is supplied through the extended power supply bars 16 and 17.
In addition, when the unit 10 and power supply unit 18 forming the prescribed ventilation path are arranged only on the upper and lower sides or to the right and left sides or to the forward and backward, respective ventilation resistances are different, ventilation within the enclosure 1 is unbalanced at the time of cooling and thereby the cooling efficiency is deteriorated. On the other hand, a problem in that a dead space is generated by a balanced co-arrangement resulting in the external appearance becoming large in size.
FIG. 5 is a detailed side elevation of the structure shown in FIG. 3. The unit 10 which is formed using the one board substrate 19, which is engaged with both sides of bus plate 13 through the post 14, an air cover 22 which covers the one board substrate 19 and a power supply unit 18 provided with the output terminals 18A, 18B are arranged together within the enclosure 1. Moreover, a duct 6 and a fan unit 7 are provided at the upper and lower end portions of the unit 10 and power supply unit 18.
Drive of the fans 8 takes the external air in the direction of arrow A from the bottom part 1B of the enclosure 1, exhausts in the direction of arrow mark B from the ceiling part 1A and cools the unit 10 and power supply unit 18.
In such a structure, since the power source of the power supply unit 13 is supplied by the extended power supply bars 16 and 17, the power supply path is long resulting in a voltage drop. Moreover, a dead space with internval S is created between the unit 10 and power supply unit 18 and only the external appearance of the enclosure 1 becomes large in size.
Moreover, the structure shown in FIG. 5 has also been a problem in the air cooling that because the unit 10, forming the one board substrate 19, and the power supply unit have different ventilation resistances, a part of the exhaust air is taken in the direction of arrow mark E during exhaustion from the ceiling part 1A as shown in FIG. 5 and high temperature air to be exhausted remains within the enclosure 1, lowering the cooling efficiency.
It is also a problem of the existing structure from the point of view of cost and mounting efficiency that a separating plate must be provided between the power supply 18 and the unit 10 or a duct which directly opens at least the one exhaust aperture to the external side of enclosure must be provided in order to adjust the migration of exhaust air and the balance in the amount of flowing air.